Composite implant coating

ABSTRACT

A coating layer, for example PEEK or titanium foil, shields a bone implant surface from wearing interactions with surfaces of bone and/or other implants. The coating prevents shedding particles which are difficult to distinguish from evidence of potentially dangerous conditions, for example, microorganism contamination and/or degenerating tissue. Methods and structures for securing a coating layer are described. Other uses and implementations of coating layers are described.

RELATED APPLICATIONS

This application is a National Phase of PCT Patent Application No.PCT/IL2013/050927 having International filing date of Nov. 11, 2013which claims the benefit of priority under 35 USC § 119(e) of U.S.Provisional Patent Application Nos. 61/841,966 filed on Jul. 2, 2013 and61/724,983 filed Nov. 11, 2012. The contents of the above applicationsare all incorporated by reference as if fully set forth herein in theirentirety.

The present application is also related to International PatentApplication No. PCT/IB2010/050225 to Beyar, filed on Jan. 18, 2010; toInternational Patent Application No. PCT/IB2011/052468 to Globerman,filed on Jun. 7, 2011; and to U.S. Provisional Patent Applications Nos.61/586,853, 61/617,067 and 61/641,900, all to Beyar, filed on Jan. 16,2012, Mar. 29, 2012, and May 30, 2012, respectively.

The contents of the above applications are all incorporated by referenceas if fully set forth herein in their entirety.

FIELD AND BACKGROUND OF THE INVENTION

The present invention, in some embodiments thereof, relates to compositematerial bone implant devices and to manufacturing methods for suchdevices. More particularly, but not exclusively, the invention in someembodiments relates to such devices and methods as applied to implantdevices formed of fiber-reinforced polymer matrices. Still moreparticularly, the invention in some embodiments relates to the surfacecharacteristics of such implant devices, such as may be conferred, forexample, by a surface coating.

Carbon fiber composite bone plates provide advantages in some propertiesover bone plates made of metal. A rigid metal bone plate createsrelatively high stresses in certain regions of the bone, withinsufficient load transfer, resulting in stress shielding. Both highstress and stress shielding can cause bone deterioration and resorption,leading to areas of bone weakness and loss of bone support for theimplant.

Non-metal implants made of a lighter and more flexible material, yethaving sufficient strength for load bearing, have been suggested in thepast. In particular, composite material implants, for example formed ofpolymer reinforced with fibers, are discussed in U.S. Pat. No.4,750,905; U.S. Pat. No. 5,181,930; U.S. Pat. No. 5,397,358, U.S. Pat.No. 5,009,664, U.S. Pat. No. 5,064,439, U.S. Pat. No. 4,978,360, andU.S. Pat. No. 7,419,714 the disclosures of which are incorporated hereinby reference. Bone implants with coatings with properties affecting, forexample, osteo-integration, bone regrowth, and biomimetic properties arediscussed in European Patent Application EP19850304670, published asEP0169001; International Patent Application No. PCT/IB2004/003260,published as WO2006038056, International Patent Application No.PCT/CH2000/000382, published as WO2002004038; and European PatentApplication EP20090702015, published as EP2245209.

The present invention addresses improvements in the above-noted areas,and in other areas of composite bone implant technology.

SUMMARY OF THE INVENTION

The present invention, in some embodiments thereof, relates to compositematerial bone implant devices and to manufacturing methods for suchdevices. More particularly, but not exclusively, the invention in someembodiments relates to such devices and methods as applied to implantdevices formed of fiber-reinforced polymer matrices. Still moreparticularly, the invention in some embodiments relates to the surfacecharacteristics of such implant devices, such as may be conferred, forexample, by a surface coating.

According to an aspect of some embodiments of the present invention,including, for example, any of the embodiments described herein, thereis provided a bone implant comprising: a body of fiber-reinforcedpolymer composite construction; and at least one layer of reinforcementfiber-free PEEK which shields said body from wearing contacts over atleast one exterior facing surface region of said body.

According to some embodiments of the invention, including, for example,any of the embodiments described herein, the layer of reinforcementfiber-free PEEK comprises a layer molded to said body by compressionmolding.

According to some embodiments of the invention, for example, any of theembodiments described herein, the shielding comprises alteration of theappearance of particles shed from said bone implant.

According to an aspect of some embodiments of the present invention, forexample, any of the embodiments described herein, there is provided animplantable bone plate comprising: a body of fiber-reinforced polymercomposite construction; and at least one layer which shields the bodyfrom wearing contacts over at least one exterior facing surface regionof the body.

According to some embodiments of the invention, for example, any of theembodiments described herein, the shielding is by interposition betweenthe body and a wearing surface.

According to some embodiments of the invention, for example, any of theembodiments described herein, the wearing contacts comprise contactswith bone, and the coating is on a side of the implantable bone platewhich contacts bone when the implantable bone plate is implanted.

According to some embodiments of the invention, for example, any of theembodiments described herein, the shielding is by conforming against thebody.

According to some embodiments of the invention, for example, any of theembodiments described herein, the wearing contacts comprise contactswhich would shed particles from the body.

According to some embodiments of the invention, for example, any of theembodiments described herein, the wearing contacts comprise contactswhich would create fractures in the body.

According to some embodiments of the invention, for example, any of theembodiments described herein, the at least one layer conforms againstthe exterior-facing surface region.

According to some embodiments of the invention, for example, any of theembodiments described herein, the at least one layer conforms againstall exterior-facing surface regions on one side of the body.

According to some embodiments of the invention, for example, any of theembodiments described herein, the at least one layer conforms againstall exterior-facing surface regions of the body.

According to some embodiments of the invention, for example, any of theembodiments described herein, at least one edge region of the at leastone layer is encased by material of the bone plate.

According to some embodiments of the invention, for example, any of theembodiments described herein, the material comprises a portion of thebody.

According to some embodiments of the invention, for example, any of theembodiments described herein, the material comprises an extrusion of thebody.

According to some embodiments of the invention, for example, any of theembodiments described herein, the extrusion comprises a shank and ahead; the shank being attached at one end to the body, and the headbeing attached to the other end of the shank; the head being sized andpositioned to interfere with the movement of the at least one layerrelative to the body.

According to some embodiments of the invention, for example, any of theembodiments described herein, the extrusion is flanged.

According to some embodiments of the invention, for example, any of theembodiments described herein, the material comprises at least a portionof an at least second layer.

According to some embodiments of the invention, for example, any of theembodiments described herein, the at least second layer overlaps andconforms against at least a portion of the edge region.

According to some embodiments of the invention, for example, any of theembodiments described herein, the material comprises a restrainingstrip.

According to some embodiments of the invention, for example, any of theembodiments described herein, the restraining strip is bonded to thebody.

According to some embodiments of the invention, for example, any of theembodiments described herein, the edge region of the layer is heldwithin a recess of the body, the recess being at least partially filledby the restraining strip.

According to some embodiments of the invention, for example, any of theembodiments described herein, the edge region of the layer comprises aportion which is bent and within a recess of the body, the recess beingat least partially filled by the restraining strip.

According to some embodiments of the invention, for example, any of theembodiments described herein, at least one region of the at least onelayer is conformed against an interior-facing surface of the body.

According to some embodiments of the invention, for example, any of theembodiments described herein, the interior-facing surface is within ahole.

According to some embodiments of the invention, for example, any of theembodiments described herein, at least one region of the at least onelayer is conformed against a chamfer of the body.

According to some embodiments of the invention, for example, any of theembodiments described herein, the chamfer is bounded on at least oneside by a surface within a hole.

According to some embodiments of the invention, for example, any of theembodiments described herein, at least a portion of the body isconformed against an edge surface of the at least one layer.

According to some embodiments of the invention, for example, any of theembodiments described herein, the conformed portion comprises a pin.

According to some embodiments of the invention, for example, any of theembodiments described herein, the conformed portion attaches to aflange.

According to some embodiments of the invention, for example, any of theembodiments described herein, at least one edge surface of the at leastone layer is conformed against a portion of the body.

According to some embodiments of the invention, for example, any of theembodiments described herein, at least a portion of the layer comprisesa polymer material.

According to some embodiments of the invention, for example, any of theembodiments described herein, at least a portion of the layer is made ofthe matrix material component of the fiber-reinforced polymer composite.

According to some embodiments of the invention, for example, any of theembodiments described herein, at least a portion of the layer is made ofPEEK.

According to some embodiments of the invention, for example, any of theembodiments described herein, at least a portion of the layer is made ofmetal.

According to some embodiments of the invention, for example, any of theembodiments described herein, at least a portion of the layer is made oftitanium.

According to some embodiments of the invention, for example, any of theembodiments described herein, the at least one layer comprises at leasttwo sublayers made of different materials.

According to some embodiments of the invention, for example, any of theembodiments described herein, the pin comprises an insertion whichpartially penetrates the material of the body.

According to an aspect of some embodiments of the present invention, forexample, any of the embodiments described herein, there is provided amethod for manufacturing an implantable bone implant comprising: forminga body of fiber-reinforced polymer composite construction, preparing atleast one coating layer for the bone implant, and compression moldingthe bone implant together with the prepared at least one layer; suchthat the at least one coating layer is restrained against the surface ofthe body; and wherein the preparing comprises positioning the coatinglayer with respect to a surface of the body so that it shields thesurface from wearing contacts.

According to some embodiments of the invention, for example, any of theembodiments described herein, the preparing comprises perforating the atleast one coating layer.

According to some embodiments of the invention, for example, any of theembodiments described herein, the bone implant is a bone plate.

According to some embodiments of the invention, for example, any of theembodiments described herein, the bone implant is a bone screw.

According to an aspect of some embodiments of the present invention, forexample, any of the embodiments described herein, there is provided animplantable bone plate comprising: a body of fiber-reinforced polymercomposite construction; and at least one metal mesh structure integratedwith the body.

According to some embodiments of the invention, for example, any of theembodiments described herein, the at least one metal mesh structurecomprises a layer region conforming to a surface of the body.

According to some embodiments of the invention, for example, any of theembodiments described herein, the at least one metal mesh structure isat least partially embedded in the body.

According to some embodiments of the invention, for example, any of theembodiments described herein, the at least one metal mesh structure iscomprised of titanium.

According to some embodiments of the invention, for example, any of theembodiments described herein, the at least one metal mesh structure iscomprised of radio-opaque material.

According to some embodiments of the invention, for example, any of theembodiments described herein, the bone implant is a bone plate.

According to some embodiments of the invention, for example, any of theembodiments described herein, the bone implant is a bone screw.

According to some embodiments of the invention, for example, any of theembodiments described herein, the bone implant is a bone nail.

According to some embodiments of the invention, for example, any of theembodiments described herein, the coating layer comprises PEEK.

According to some embodiments of the invention, for example, any of theembodiments described herein, the coating layer comprises carbonfiber-free PEEK.

Unless otherwise defined, all technical and/or scientific terms usedherein have the same meaning as commonly understood by one of ordinaryskill in the art to which the invention pertains. Although methods andmaterials similar or equivalent to those described herein can be used inthe practice or testing of embodiments of the invention, exemplarymethods and/or materials are described below. In case of conflict, thepatent specification, including definitions, will control. In addition,the materials, methods, and examples are illustrative only and are notintended to be necessarily limiting.

BRIEF DESCRIPTION OF THE DRAWINGS

Some embodiments of the invention are herein described, by way ofexample only, with reference to the accompanying drawings. With specificreference now to the drawings in detail, it is stressed that theparticulars shown are by way of example and for purposes of illustrativediscussion of embodiments of the invention. In this regard, thedescription taken with the drawings makes apparent to those skilled inthe art how embodiments of the invention may be practiced.

In the drawings:

FIG. 1A schematically illustrates a perspective view of an exemplarycoated bone plate coated on at least one surface, in accordance withsome exemplary embodiments of the present invention;

FIGS. 1B-1C schematically illustrate perspective, sectional views of thebone plate of FIG. 1A in overview and/or in detail, in accordance withsome exemplary embodiments of the present invention;

FIG. 2A schematically illustrates a perspective view of an exemplarycoated bone plate coated on at least one hole-interior surface, inaccordance with some exemplary embodiments of the present invention;

FIGS. 2B-2D schematically illustrate perspective, sectional views of thebone plate of FIG. 2A in overview and/or in detail, in accordance withsome exemplary embodiments of the present invention;

FIG. 3A schematically illustrates a perspective view of an exemplarycoated bone plate coated on at least one hole chamfer surface, inaccordance with some exemplary embodiments of the present invention;

FIGS. 3B-3D schematically illustrate perspective, sectional views of thebone plate of FIG. 3A in overview and/or in detail, in accordance withsome exemplary embodiments of the present invention;

FIG. 4A schematically illustrates a perspective view of an exemplarycoated bone plate coated on at least two surfaces, in accordance withsome exemplary embodiments of the present invention;

FIGS. 4B-4D schematically illustrate perspective, sectional views of thebone plate of FIG. 4A in overview and/or in detail, in accordance withsome exemplary embodiments of the present invention;

FIG. 5A schematically illustrates a perspective view of an exemplarycoated bone plate coated on at least one chamfer and/or rim surface, inaccordance with some exemplary embodiments of the present invention;

FIGS. 5B-5D schematically illustrate perspective, sectional views of thebone plate of FIG. 5A in overview and/or in detail, in accordance withsome exemplary embodiments of the present invention;

FIG. 6A schematically illustrates a perspective view of an exemplarycoated bone plate coated on at least two surfaces and having at leastone region where coating layers overlap, in accordance with someexemplary embodiments of the present invention;

FIGS. 6B-6D schematically illustrate perspective, sectional views of thebone plate of FIG. 6A in overview and/or in detail, in accordance withsome exemplary embodiments of the present invention;

FIG. 7A schematically illustrates a perspective view of an exemplarycoated bone plate coated on at least one surface and having at least oneregion where a coating layer is held in place by a pin formation, inaccordance with some exemplary embodiments of the present invention;

FIGS. 7B-7E schematically illustrate perspective, sectional views of thebone plate of FIG. 7A in overview and/or in detail, in accordance withsome exemplary embodiments of the present invention;

FIG. 8A schematically illustrates a perspective view of an exemplarycoated bone plate coated on at least one surface and having at least oneregion where a coating layer is held in place by an elongated pinformation, in accordance with some exemplary embodiments of the presentinvention;

FIGS. 8B-8E schematically illustrate perspective, sectional views of thebone plate of FIG. 8A in overview and/or in detail, in accordance withsome exemplary embodiments of the present invention;

FIGS. 9A-9C schematically illustrate sectional views of phases in theextrusive formation of a retaining structure for restraining a coatinglayer to the body of a bone plate implant, in accordance with someexemplary embodiments of the present invention;

FIG. 10A schematically illustrates a perspective view of an exemplarycoated bone plate coated on at least one surface by at least two coatinglayers, in accordance with some exemplary embodiments of the presentinvention;

FIGS. 10B-10D schematically illustrate perspective, sectional views ofthe bone plate of FIG. 10A in overview and/or in detail, in accordancewith some exemplary embodiments of the present invention;

FIGS. 11A-11C schematically illustrate sectional views of phases in theextrusive formation of a retaining structure for restraining a coatinglayer to the body of a bone plate implant, in accordance with someexemplary embodiments of the present invention;

FIG. 12A schematically illustrates a perspective view of an exemplarycoated bone plate coated on at least one surface and having at least oneregion where a coating layer is held in place by a retaining structure,in accordance with some exemplary embodiments of the present invention;

FIGS. 12B-12D schematically illustrate perspective, sectional views ofthe bone plate of FIG. 12A in overview and/or in detail, in accordancewith some exemplary embodiments of the present invention;

FIG. 13A schematically illustrates a perspective view of an exemplarycoated bone plate coated on at least one surface and having regionswhere a coating layer is held in place by one or more retainingstructures, in accordance with some exemplary embodiments of the presentinvention;

FIG. 13B schematically illustrates a perspective view of an exemplarycoated bone plate coated on at least one surface and having regionswhere a coating layer is held in place by one or more retainingstructures, in accordance with some exemplary embodiments of the presentinvention;

FIGS. 14A-14D schematically illustrate perspective views in whole,sectionally, and/or in detail of an exemplary coated bone plate havingan aperture-patterned layer on at least one surface, in accordance withsome exemplary embodiments of the present invention;

FIGS. 15A-15D schematically illustrate surface views of exemplaryaperture patterns used in some exemplary embodiments to comprise a mesh(apertured) layer, in accordance with some exemplary embodiments of thepresent invention;

FIGS. 16A-16B schematically illustrate in perspective sectional viewregions of exemplary bone having a mesh (apertured) structure embeddedwithin the implant body, and/or underneath a coating layer, inaccordance with some exemplary embodiments of the present invention;

FIGS. 17A-17B schematically illustrate mold and part components forcoating of a bone screw by compression molding, in accordance with someexemplary embodiments of the present invention; and

FIG. 18 schematically illustrates a bone nail coated with PEEK bycompression molding, in accordance with some exemplary embodiments ofthe present invention.

DESCRIPTION OF SPECIFIC EMBODIMENTS OF THE INVENTION

The present invention, in some embodiments thereof, relates to compositematerial bone implant devices and to manufacturing methods for suchdevices. More particularly, but not exclusively, the invention in someembodiments relates to such devices and methods as applied to implantdevices formed of fiber-reinforced polymer matrices. Still moreparticularly, the invention in some embodiments relates to the surfacecharacteristics of such implant devices, such as may be conferred, forexample, by a surface coating.

Overview

An aspect of some embodiments of the invention relates to a coatinglayer which shields a portion of a bone implant surface from wearinginteractions with bone and/or with other bone implant componentsurfaces. In some embodiments of the invention, the coating layercomprises a polymer, for example PEEK. In some embodiments of theinvention, the coating layer is of a metal foil, such as titanium.

According to some embodiments, other coating materials are used, forexample, as described hereinbelow. In some embodiments of the invention,the coated bone implant is a bone plate, a bone screw, and/or a bonenail.

A potential advantage of such a coating is to prevent the shedding ofparticles from an implant. Shed particles may be difficult todistinguish from evidence of potentially dangerous conditions, forexample, microorganism contamination and/or degenerating tissue. Acoating may also provide an advantage with respect to inspection and/oraesthetics. There may be a particular potential advantage in one or moreof these respects when shed particles are dark.

An aspect of some embodiments of the invention relates to a polymercoating layer (for example, PEEK or PEKK) for a bone implant having acomposite, fiber-reinforced body, wherein the polymer coating issubstantially free of reinforcing fibers of the type used in the implantbody. In some embodiments, substantially free means having <10% of thereinforcing fiber content of the implant body, <5%, <1%, <0.5%, <0.1%,or less than an intermediate, greater or lesser threshold of relativereinforcing fiber concentration. In some embodiments the polymer coatingis entirely free of reinforcing fibers. Optionally, the polymer coatingcontains fibers of a different composition than the reinforcing fibersof the implant body. In some embodiments, the coating layer polymer iscomprised of material of a composition matching the material of thecomposite material matrix.

An aspect of some embodiments of the invention relates to a plurality oflayers for the coating. In some embodiments, coatings are overlaid overall or a portion of their extent, with each layer potentially providingspecific properties to the bone implant according to its constructionand composition. In some embodiments, coatings are provided withconstruction and composition determined differently for differentregions of the bone implant; for example, differently for a top- and fora bone-facing surface, or differently for a hole- and non-hole-surface.Non-hole surfaces in general, and top-facing, bone-facing, andouter-side facing surfaces in particular are exterior surfaces of thebone implant. In some embodiments, one or more regions of overlapbetween layers contribute to the attachment of at least one of thelayers to the bone implant.

An aspect of some embodiments of the invention relates to radio-opaqueelements which are embedded in, overlie and/or underlie a coating.Optionally, the radio-opaque elements are arranged in an encodingconfiguration. Radio-opaque elements may provide an advantage fordetermining orientation and/or identification of a bone implant from aradiographic image.

An aspect of some embodiments of the invention relates to groupedapertures in layer structures of a bone plate implant. In someembodiments, grouped apertures exist within, for example, a mesh, grid,screen, grating, weave, and/or wire winding.

In some embodiments, grouped apertures are collectively comprised in aregion of relative transparency to one or more imaging modalities, forexample, MRI, X-ray, CT, and/or visible light. In some embodiments,apertures are holes in a layer of material. In some embodiments,apertures are defined as such according to transparency or relativetransparency in an imaging modality (for example, in the sense that aglazed window pane is an aperture for visible light). In particular,relative thinness of a region potentially creates an aperture forimaging through. In some embodiments, the mesh (apertured) structure ismade of metal. In some embodiments, the mesh structure is a coatingand/or an undercoating. In some embodiments, the mesh structure isintegrated into the bulk structure of the bone implant. In someembodiments, the material forming the mesh structure is radio-opaquerelative to the bulk structure of the bone plate implant.

An aspect of some embodiments of the invention relates more generally tocomposite material bone plate implants coated with material whichdiffers from the bulk material composition of the implant. Such acoating may confer a desired property to the implant.

An aspect of some embodiments of the invention relates to processes,methods, and/or structural features used to secure a coating to acomposite material bone plate implant. A coating may be secured, forexample, by adhesion or bonding; and/or secured by geometrical restraintand/or frictional forces. A coating may be made to conform to thesurface of an underlying bone implant in different ways: for example, bybeing initially created on the implant surface (for example, by sprayingor dip-coating), or by being separately created and then pressed ontothe implant surface (for example, by compression molding). A conformingcoating generally follows the bulk outlines of the underlying boneimplant. In some embodiments, coatings also conform with bone implantstructures such as chamfers and/or holes. In some embodiments, aconforming coating has shape details which diverge from the underlyingimplant body. In some embodiments, this occurs, for example, at pointswhere implant body and coating layer interact (including at restrainingpins or strips), to provide shape-locking attachment, or where two ormore coating layers are shaped around one another, as herein described.

An aspect of some embodiments of the invention relates to pin formationswhich comprise a shank that fits into an aperture of the coating layerand attaches to and/or is continuous with the material of the bone plateimplant underneath. In some embodiments, the shank is topped by a capwhich interferes with the removal of a coating layer.

An aspect of some embodiments of the invention relates to the surfaceappearance of the implant. In some embodiments, a coating is providedwhich changes the surface appearance to meet an aesthetic requirement,for example, a positive aesthetic requirement such as a need to presentthe appearance of a metallic surface, or a negative requirement, such asthe need to present a surface which is not black.

Before explaining at least one embodiment of the invention in detail, itis to be understood that the invention is not necessarily limited in itsapplication to the details of construction and the arrangement of thecomponents and/or methods set forth in the following description and/orillustrated in the drawings. The invention is capable of otherembodiments or of being practiced or carried out in various ways.

Bone Wear Shielding

Reference is now made to FIGS. 1A-1C which schematically illustrateperspective views in whole or sectionally, and/or in detail 510, ofexemplary coated bone plate implant 500 coated on at least one surface505, 550, in accordance with some exemplary embodiments of the presentinvention. The example of FIG. 1A illustrates a form like that of adistal radius plate such as may be used in wrist fracture repairtreatments.

In some embodiments of the invention, a coating surface with anincreased hardness, fracture toughness, and/or decreased coefficient offriction with respect to the uncoated surface of the bone implant isselected. There is a potential advantage achievable thereby in reducingthe number of particles shed. This potential advantage applies even whenthe bulk material of a bone plate implant is mechanically sufficient foruncoated use in a bone implant, even in contact with wearing surfacessuch as bone. A surface with increased fracture toughness with respectto the uncoated bone implant surface provides a potential advantage byreducing the occurrence of fractures which spread to the body of theimplant and undermine structural integrity.

It should be noted that the surfaces of a bone plate implant arecommonly exposed to different environments during and afterimplantation. In particular, in some embodiments of bone implants havingtwo surfaces of greatest extent (for example, surfaces 705 and 707 ofFIG. 6B) one side (for example, 707, the “bone” or “bottom” side of theimplant) is installed against bone, while the other (“top” side 705)contacts soft tissue. Bone contact is a particular source of contactwear on a bone implant.

In some embodiments of the invention a surface is modified so thatparticles it does shed are distinctive and/or preferred in size and/orappearance. For example, the surface is chosen to present a metallic,transparent, or some clearly artificial coloration and/or appearance. Insome embodiments, the surface is chosen to present a textured and/orpatterned appearance. Particles shed from a bone implant surface due tonormal wearing interactions may not be readily distinguishable fromevidence of potentially dangerous conditions, for example, microorganismcontamination and/or degenerating tissue. Carbon fibers, for example,contribute to shed particles a dark (gray or black) coloration which mayappear pathological. In some embodiments, a surface is modified so thatshed particles are of a predetermined size range. Optionally, the sizerange is selected for its biocompatibility; for example, a largerparticle size range may be more biocompatible than a size rangecomprising nanoparticles smaller than a micron, smaller than 0.5 micron,or smaller than 0.1 microns.

A potential advantage is provided by a surface which sheds particlesthat are clearly distinguishable from evidence of a dangerous condition,and/or which sheds fewer particles. Shedding of few particles may be anadvantage, for example, to reduce staining of surrounding tissue, and/orto make inspection of an implant site easier.

In some exemplary embodiments of the invention, a bone plate implant 500is coated by coating layer 530 over a surface 505 or portion of asurface 550 which, when implanted, is in contact with hard material,such as bone, over at least a portion of its extent.

It is potentially advantageous to provide a surface material chosen fora potentially enhanced wear durability compared to the native surface ofa bone plate implant. In some embodiments, the material of coating layer530 of a bone plate implant 500 is chosen to potentially provide highsurface hardness and/or fracture toughness to the implant. The hardnessis chosen, for example to be greater than 20 HRC, greater than 25 HRC,or greater than 30 HRC. ATI Ti-6Al-4V, for example, has a hardnessgreater than 30 HRC. A chosen fracture toughness for a coating materialis for example, greater than 1 MPa·m^(1/2), greater than 2 MPa·m^(1/2),or greater than 5 MPa·m^(1/2). In some embodiments, the implant iscoated with one of the following materials: titanium (Ti), titaniumnitride (TiN) (Lugscheider, 1999; Kim, 2007), titanium aluminum nitride(Ti—Al—N), another titanium ceramic or alloy, diamond like carbon (DLC),another ceramic or metal material, or another suitable material. Suchmaterials provide the potential advantage of conferring surface hardnessthat improves, for example, on the hardness of a composite materialsurface of carbon fiber in PEEK. This may in turn provide an advantageby reducing particle shedding due to contacts with bone.

In some exemplary embodiments, the coating layer 530 of a bone plateimplant is chosen to potentially reduce a coefficient of friction. Areduced coefficient of friction may provide an advantage for weardurability. Such a coating is described, for example, by Zheng (2012). ADLC film may also provide a lowered coefficient of friction. In someembodiments, a friction reducing layer is added over a layer of materialselected for hardness and/or toughness.

In some embodiments, the debris-shedding properties of a bone plateimplant surface 505 are changed, for example, by coating the implantwith a material which does not shed particles that may be confused withevidence of a dangerous condition.

In some embodiments, this is the material of the composite matrix.Optionally, for example, a PEEK-carbon fiber composite material iscoated with PEEK.

Optionally, another material with desirable appearance characteristicsis chosen. This may provide an advantage, for example, by modifying thenature of shed particles so that they are clearly distinct from evidenceof a dangerous condition. Such an advantage is obtainable even if thenet number of particles shed is not affected, or increased.

In some exemplary embodiments, the coating layer 530 of a bone plateimplant is chosen to affect the bioreactivity of the surface. In someembodiments, the material is chosen to promote osteo-integration. Such amaterial may be, for example, titanium oxide or hydroxyapetite.

Exemplary Manufacturing Methods

A coating may be provided according to one or more of a selection ofmanufacturing techniques. In some embodiments corresponding to boneplate implant 500, and to other coated bone implants herein described,coating is performed using compression molding.

In some embodiments corresponding to bone plate implant 500, and othercoated bone implant embodiments as herein described, coating is by othermethods, alone or in combination. In some embodiments, for example,physical vapor deposition (PVD) (Rahamathunnisa, 2007) is used.Optionally, PVD follows preparation of the surface of the implant; forexample, by grid blast, bombardment of argon ionized ions, or othersurface treatment. In some embodiments, the coating is added using avacuum plasma spray (VPS) technique, optionally following preparation ofthe surface of the implant (Ha, 1997; Beauvais).

Other contemplated methods for application of a coating includedip-coating, spray-coating, chemical vapor deposition, etching, surfacepolymerization, electrochemical deposition, electroplating and 3Dprinting. Other contemplated forms of application include, for exampleas film, particles, vapor, and/or as solution. Examples of the materialcomposition of a coating include metals, polymers, ceramics andcomposites.

Compression Molding for Bone Plate Implant Surfacing

According to an aspect of some exemplary embodiments of the invention, abone plate implant 500 is coated with at least one separately preparedlayer that is attached to the bone plate implant. A separately preparedlayer may be, for example, a metal foil, a polymer film, a polymer tape,and/or another material which is rendered into a flat form susceptibleof layering onto a surface. In some embodiments of the invention, theattachment is by adhesion, for example using an adhesive, or for exampleby preparing surfaces so that they adhere after undergoing amanufacturing step such as compression molding. In some embodiments,attachment is mechanical, for example, due to restraining interactionsbetween the implant body and one or more layers, between layers, orbetween some combination of layers and implant body. Layers may bephysically and/or chemically integrated into the body of the implantduring manufacturing. In some embodiments, layer attachment isestablished using compression molding. A potential advantage ofcompression molding is to allow bonding and/or mechanical restraint ofcoating layers to a bone plate implant surface, depending on thespecifics of material, geometry, and coating method.

In some embodiments, a coating layer 530 is molded along with the mainbody of the bone plate implant 500. In some embodiments, the surface ofan already shaped bone plate implant 500 is modified via a secondarycompression molding step.

In some embodiments, the surface is modified via a tertiary or greatercompression molding step. In some embodiments, another coating method,for example one of those listed above, is used to apply at least a firstcoat to a bone plate implant 500 before or after a compression moldingstep which applies and/or establishes the attachment of a furthersurface treatment such as an additional layer of material.

In some embodiments, material is layered over at least one region of theimplant 505, 550 to form a coating layer 530. In some embodiments,layered material is in the form of a metal foil; for example, titanium,titanium alloy, or another metal.

Alternatively or additionally, layered material is in the form of tape;for example, a tape of PEEK, PEKK or another polymer. According to theembodiment, the at least one region is, for example: all implantsurfaces, one or more sides and/or portions thereof, and/or all orportions of one or more interior surfaces. In some embodiments, theportion of the surface covered by a coating layer is 10%, 20%, 50%, 80%,100%, or another intermediate fraction of the total surface. In someembodiments, the portion covered is continuous. In some embodiments, theportion covered is discontinuous.

According to the embodiment, the layered thickness of foil, polymer,and/or other coating materials, before and/or after compression, rangesbetween, for example: between 100 nanometers and 1 micron, between 1micron and 10 microns, between 10 microns and 100 microns, between 100microns and 1 mm, and between 1 mm and 2 mm. In some embodiments, adifferent thickness is applied at different regions of the implant. If amaterial is to be on an exposed surface, it is chosen to bebiocompatible (potentially comprising, for example, biocompatiblepolymers, metal alloys comprising titanium, nickel-titanium, stainlesssteel, and/or another material such as hydroxylapatite). Optionally, ifburied under more superficial layers, materials which are notbiocompatible are used.

The wrapped composite is put under pressure; for example, a pressurehigher than 50 atm, 100 atm, 400 atm, 700 atm, or 1000 atm. In someembodiments, the pressure used is between 100 atm and 150 atm.Optionally, the temperature is selected so that compression moldinginduces integration between the outer layer and the matrix below; forexample, between 380° C., 400° C., 405° C. or 410° C. In someembodiments, the tolerance range on the temperature is ±1° C., ±2° C.,±5° C., or ±10° C.

Optionally, the temperature is selected to be slightly above the polymermelting point. Optionally, the temperature and/or molding pressure isselected so that compression molding causes at least partial flow of oneor more of the applied layer materials.

In some embodiments, material layers of potentially different materialcomposition are added as a surface modification coating to be formed inthe same compression molding step. This is further discussed herein inrelation to FIGS. 10A-10D. Optionally, the material is added in the formof tapes. Relative to the implant overall length or overall width, thetape width may be, for example, 1%, 5%, 10%, 50%, or 100% or more of theimplant's size. In some embodiments, tapes are self-overlapping.According to the embodiment, tape is wound around any axis of the boneimplant. Optionally, different lengths of tape are wound in differentdirections.

Optionally, material layers are applied separately and molded in atleast two compression molding steps. Optionally, material layers areplaced in a predetermined order, chosen according to their properties,to produce a bone implant of predetermined properties. Optionally, thepredetermined order varies at different locations on and/or within theimplant. Optionally, material layers are placed with predetermined, andpotentially different orientations.

More specifics of compression molding use in manufacturing coatings forbone plate implants are discussed herein, in connection with thedrawings.

Coating Holes

Reference is now made to FIGS. 2A-2D which schematically illustrateperspective views in whole or sectionally, and/or in detail 410, 420 ofexemplary coated bone plate 400 coated on at least one hole interiorsurface 440, 450, in accordance with some exemplary embodiments of thepresent invention. The example of FIG. 2A illustrates a form like thatof a diaphyseal plate such as may be used in long bone repairtreatments.

Wearing interactions upon surfaces of a bone plate implant may occurwith other implant components, for example, screws. In some embodimentsof the invention, a coating layer is provided which intrudes into holes.A potential advantage of a coating which enters a hole is to provideanchoring for the coating layer; for example by adherence and/or byshape-locking.

In some exemplary embodiments of the invention, a bone plate implant 400is coated by coating layer 430 which intrudes into a hole and covers atleast a portion of an interior hole surface, 440, 450. Optionally,coating layer 430 is contiguous with portions of a coating layercovering another surface 405, which, when implanted, is in contact withbone. In some embodiments, coating layer 430 may include a region 445which extends to cover at least a portion of a partially interior holesurface, such as a chamfer. In some embodiments, the covered height ofthe chamfer around a whole or partial circumference is at least 20%, atleast 30%, at least 50%, or 100% of the overall height of the chamfer.In some embodiments, the circumferential portion of the chamfer which iscovered is at least 20%, at least 30%, at least 50%, or 100% of the fullcircumference of the chamfer.

In some embodiments of the invention, the coating material is ductile sothat it conforms to the hole aperture during pressure molding. In someembodiments, a whole or partial insert sleeve is provided which conformsto the hole aperture, and/or is made to conform by pressure molding. Insome embodiments, coating material is cut before being applied to boneplate implant 400 so that a flap of it inserts into the hole and ispressed against a portion of the interior hole surface, for example,during pressure molding. In some embodiments, two or more such flapsinsert into the hole.

In some embodiments, the interior surface of one or more coated holes issmooth. In some embodiments, the interior surface of one or more coatedholes is threaded.

It should be noted that the presence of holes and the use of holecoatings described herein is not confined to embodiments having theshape of bone plate implant 400. For example, some embodiments shapedlike bone plate 500, or with another shape suitable for a bone plate,are manufactured with holes. In some embodiments, at least one of theseholes is at least partially coated.

In some embodiments of the invention, compression molding duringmanufacture forces a plastic layer material, for example a foil or apolymer tape, to conform to at least a portion of the interior surface440, 450 of one or more holes in a bone plate implant 400. This mayprovide advantages over coating techniques for which a hole region isinaccessible or difficult to coat. It may provide advantages over theuse of pre-formed hole inserts, for example, by reducing the complexityof manufacture.

In some embodiments, the form assumed by a coating layer may itselfserve to restrain the coating upon the body of the bone implant. Forexample, a foil coating may insert into, curve around, and/or wraparound a portion of the implant, restricting the directions in which thecoating may move relative to the bone implant body without furtherdeformation. In some embodiments, shape locking prevents relative motionaltogether. Such shape locking is a potential advantage of applying acoating layer with at least partial hole penetration.

Reference is now made to FIGS. 3A-3D which schematically illustrateperspective views in whole or sectionally, and/or in detail 310, 320, ofexemplary coated bone plate 300 coated on at least one hole chamfersurface 340, 350, in accordance with some exemplary embodiments of thepresent invention.

In some embodiments, a hole is coated throughout its extent. A potentialadvantage of this is to ensure complete protection of hole surfacesexposed to wearing interactions. Another potential advantage is toprovide shape-locking.

In some exemplary embodiments of the invention, a bone plate implant 300is coated by coating layer 330 which intrudes into a hole region so asto coat at least a portion of a chamfer and/or an interior hole surface,340, 350. In some embodiments, the covered height of the chamfer arounda whole or partial circumference is at least 20%, at least 30%, at least50%, or 100% of the overall height of the chamfer. In some embodiments,the circumferential portion of the chamfer which is covered is at least20%, at least 30%, at least 50%, or 100% of the full circumference ofthe chamfer. Optionally, coating layer 330 is contiguous with portionsof a coating layer covering another surface 305.

In some embodiments of the invention, fully coated holes are produced bya combination of the coated embodiment of bone plate implant 300 withthe coated embodiment of bone plate implant 400. Optionally, such anembodiment is produced in one or in separate compression molding steps.Optionally, layers from entering the hole from opposing sides overlapone another. In some embodiments, a portion of the layer which entersthe hole is made thicker; for example, so as to provide additionalprotection for regions which are contacted by the threads of a screw.

Examples of coatings comprising two or more surfaces are discussed inmore detail in connection with other embodiments described herein.

Coating of Multiple Surfaces

Reference is now made to FIGS. 4A-4D which schematically illustrateperspective views in whole or sectionally, and/or in detail 210, 220, ofexemplary coated bone plate 200 coated on at least two surfaces 205,207, in accordance with some exemplary embodiments of the presentinvention.

According to some exemplary embodiments of the invention, a bone plateimplant is coated on surfaces additional or alternative to those whichare liable to wearing interactions with hard surfaces, such as bone.

Apart from debris produced by wearing interactions, there are potentialdrawbacks to the normal visual appearance of some bone plate implantsurfaces, such as surfaces of carbon fiber composite. Coloration mayinterfere with inspection of the implant for flaws such as cracks orcontamination. Coloration may alter the visual contrast of the implantwith surrounding implant elements and/or tissue.

Aesthetically, a surface with unusual coloration compared to other boneimplant materials may be distracting and/or disturbing. Carbon fiberstend to darken composites of which they are a part, potentiallycontributing to one or more of these drawbacks.

There are also potential advantages to using color as an indicator. Insome embodiments, for example, a coating color is chosen so that it isclearly distinct from endogenous colors. This may provide an advantage,for example, by helping to ensure that shed particles are not mistakenfor signs of infection and/or tissue damage. In some embodiments, layersof different colors are provided, potentially serving as an indicator ofbone implant wear.

In some exemplary embodiments of the invention, a bone plate implant 200is coated by coating layer 225, 230 over a surface 205, 207 or portionof a surface 240, 245, 250, 255. The material of coating layer 225 andcoating layer 230 may be the same, or different. Optionally, the coatingmaterial is chosen from among those discussed in connection to otherembodiments of the invention; for example, to provide wear durability orfor appearance. In some cases, the coating material is chosen from amongthose next discussed in connection with other surface properties.

Other Surface Properties

According to an aspect of some embodiments of the present invention,determination of the surface properties of a bone plate implantconferred by a coating is not limited to considerations of wearcharacteristics or appearance. Conferred properties may relate to, forexample, self-healing, and/or biological activity.

Self-Healing

According to an aspect of some embodiments of the present invention,material properties and/or the process of manufacturing and/or a processof post-manufacturing treatment is chosen or designed to introduce oneor more self-healing properties into a bone plate implant. Aself-healing property is one that, when activated, initiates a changethat tends to prevent the implant from failing to function within itsintended physical, chemical and/or biological specifications.

During manufacturing of some embodiments of the invention, one or moreself-healing agents is added at one or more predetermined locations onor within the bone implant. Optionally, a self-healing agent is added ina predetermined amount and/or concentration. Optionally, a self-healingagent is added alone. Optionally, a self-healing agent is added in aformulation. Optionally, an encapsulated agent is formulated within aninert outer shell. Optionally, a self-healing agent comprises acombination of compounds which perform their healing effect when mixed.

In some embodiments, the operation of a self-healing agent in a boneimplant is triggered by a change in the implant material with respect tooriginal specifications.

The action of self-healing can be initiated with and without an externaltrigger. Exemplifying the former, Hargou (2012), describes ultrasonicactivation of self-healing in carbon-epoxy laminates. Exemplifying thelatter, Williams (2007) describes a self-healing agent (Cytec Cycom 823)encapsulated within microparticles embedded in carbon reinforcedcomposite. When a crack begins to propagate, the sealing agent leachesfrom the particle. This tends to close the crack and prevent furtherpropagation.

In an exemplary embodiment of the invention, foils and/or polymer tapes(such as PEEK or PEKK or others), at least one of which contains aself-healing agent, are layered upon the bone implant. Such aself-healing agent may act, for example, to help seal propagating cracksoriginating near the surface of implant due to long-term cyclic loads invivo. Optionally, layers are added in a predetermined order. Optionally,layers are added with a specific orientation, for example to determinedirections in which greatest strength is added. Optionally, layerstructure varies according to position on the implant, possibly withrespect, for example, to layer number, layer thickness, layerorientation, and/or layer materials. In some embodiments of theinvention, compression molding is performed under conditions of pressureand temperature which do not damage the activity of the self-healingagent.

Biological Activity

In some exemplary embodiments, the coating of a bone plate implant ischosen to determine the osteo-conductive and/or osteo-inductiveproperties of the implant. Coatings which may improve such propertiesinclude, for example, porous titanium or hydroxyapatite (HA). In someembodiments of the invention, the coating is separable from theunderlying bone implant. A potential advantage of such a separation isto allow an osteo-integrated bone implant to be removed from an implantsite with lowered disruption to regrown bone material.

In some exemplary embodiments, the coating of a bone plate implant ischosen to potentially reduce a bacterial burden. Optionally, the outerlayer is chosen with particular attention to its smoothness, such as asmooth PEEK tape. Smoother PEEK surfaces may carry a lower bacterialload relative to similar samples having a rougher surface (Rochford,2010).

In some exemplary embodiments, the coating of a bone plate implantpresents and/or releases to the surrounding tissue a pharmaceuticallyactive material, for example, one with anti-inflammatory, antibiotic,and/or antiseptic properties (Simchi, 2011).

More than One Coated Surface

Reference is now made to FIGS. 5A-5D which schematically illustrateperspective views in whole or sectionally, and/or in detail 610, 620, ofexemplary coated bone plate 600 coated on at least one chamfer surface640, 650 and/or rim surface 655, in accordance with some exemplaryembodiments of the present invention.

In some exemplary embodiments of the invention, a bone plate implant 600is coated by coating layer 630 over a surface 605 which may includedetails such as one or more chamfered surfaces 650, 640, and/or rimsurfaces 655.

Coated surface 605 of bone plate 600, when implanted, may not be incontact with bone. However, other potential coating advantages discussedin relation to the coating of non-wearing surfaces FIGS. 4A-4D apply aswell to the embodiments of FIGS. 5A-5D; for example, modification ofsurface properties. In another example, the shape-locking advantagedescribed in connection with holes in FIGS. 2A-2D may also be provided.

Reference is now made to FIGS. 6A-6D which schematically illustrateperspective views in whole or sectionally, and/or in detail 710, 720, ofexemplary coated bone plate 700 coated on at least two surfaces 705,707, and having at least one region where coating layers 730, 735overlap, in accordance with some exemplary embodiments of the presentinvention.

In some embodiments of the invention, a top-surface coating layer on abone plate interacts with a bottom-surface (bone-facing) coating layer,for example by overlapping edges. This may provide the advantage ofhelping to restrain an overlapped layer against the body of a bone plateimplant.

In some exemplary embodiments of the invention, a bone plate implant 700is coated by at least two coating layers 730, 735 which cover at leastportions of bone implant surfaces 705, 707, and furthermore overlap inat least one region covering a bone implant surface 740, 750.

In some embodiments, the wrap-around forms of coating layers 730, 735may provide an independent shape-locking advantage, as previouslydiscussed. Another potential advantage arises from the region ofoverlap, wherein an edge region of coating layer 735 is retained byoverlapping coating layer 735. In some embodiments, one coating layermay extend around the implant to overlap itself in similar fashion.

According to the embodiment of the invention, the materials ofbottom-surface coating layer 735 and top-surface coating layer 730 arethe same, or different.

Optionally, in embodiments where materials are different, they arechosen such that the bottom-surface (bone-contacting) layer 735 materialis optimized for a surface property, such as hardness. A potentialadvantage of using the geometry of the layers, (in particular regions ofoverlap) to mutually restrain one another is, for example, that the hardmaterial may be chosen for use even having relatively poor properties ofadherence to the underlying bone plate implant material (for example atitanium foil). Optionally, the materials are chosen to be galvanicallyinert with respect to each other.

Constraints affecting material choice may be different for top-surfacelayer 730 material. In some embodiments, top-surface layer 730 is chosento have good adherence properties to the bone plate implant material,for example, PEEK. In restraining the edge regions of the lower-surfacecoating 735, the top-surface coating 730 potentially confers some of theadvantage of its own adherence properties. In some embodiments, thetop-surface coating is constructed to improve the stability of itsrestraining function; for example, it has a greater thickness, and/or isa material which assumes a relatively rigid form in the finished boneimplant. Some of these embodiments are produced, for example, in one orin separate compression molding steps.

Pin Retaining Structures

Reference is now made to FIGS. 7A-7E which schematically illustrateperspective views in whole or sectionally, and/or in detail 810, 820, ofexemplary coated bone plate 800 coated on at least one surface 805, 807,850, 860 and having at least one region where a coating layer 830, 835is held in place by a pin formation 825, 827, 828, 829, in accordancewith some exemplary embodiments of the present invention. In someembodiments, pin formations are integral to the implant. In someembodiments, pins may be supplied as components which become attached tothe body of the implant during manufacturing, for example, duringpressure molding.

In some exemplary embodiments of the invention, a bone plate implant 800is coated by at least one coating layer 830, 835 which covers at leastportions of bone implant surfaces 805, 807. Coating layer 830, 835 hasat least one aperture shaped and sized to accommodate a pin formation825, 827, 828, 829 which acts as a retaining structure, tending torestrain the coating layer to the surface 805, 807, 850, 860 of the boneplate implant body. Pin formations 825, 827, 828, 829 are attached at abase end to the body of the bone plate implant. In some embodiments,they fill the aperture they occupy. In some embodiments, they act as arestraint without completely filling the aperture they occupy; forexample, by having an annular cross-section. In some embodiments, theyrise to a level which is about flush with the surrounding coating layermaterial. In some embodiments, pin formations 825, 827, 828, 829comprise a shank that fits into the aperture, and a cap which interfereswith the removal of a coating layer. In some embodiments, pin formations825, 827, 828, 829 have a flange which covers an edge region of thesurrounding coating layer. Optionally, a pin formation 825, 827, 828,829 may protrude above or remain below or at the surface of thesurrounding coating layer material.

According to the embodiment, the shank of a pin formation and/or thecoating aperture it occupies may have a minimum cross-sectionaldimension of, for example, 0.2 mm, 0.5 mm, 1 mm, 2 mm, 5 mm, or anydimension in between; or a larger or smaller dimension. A pin formationcross section may be circular, square, oblong, or another shape suitablefor restraining the coating layer material; for example, a curved strip.

Some exemplary details of pin formation (retaining structure) form andmanufacture are discussed in relation to FIGS. 9A-9C, 11A-11C, and12A-12D.

In some embodiments of the invention, there are at least two coatinglayers 830, 835 which overlap and/or abut in at least one regioncovering a bone implant surface 850, 860; and both contain and/ortogether define at least one common aperture shaped and sized toaccommodate a pin formation 825, 827, 829 which acts as a retainingstructure on the coating layers it abuts and/or partially overlies. Insome embodiments of the invention, a bone implant surface 860, which iscoated by at least one coating layer 830, 835, may be constructed with acurvature shaped to help anchor the coating layer. Surface 860, forexample, is illustrated with a concave curvature through the thicknessof the bone implant, while having a convex curvature around its end. Thedegrees of freedom of the coating layer to move are restricted by thisgeometry, compared, for example, to a straight coating edge. A potentialadvantage of constructing a bone implant surface with differentcurvatures is to provide enhanced shape-locking.

Reference is now made to FIGS. 8A-8E which schematically illustrateperspective views in whole or sectionally, and/or in detail 910, 915,920, of exemplary coated bone plate 900 coated on at least one surface905, 907, 950, 960, 970 and having at least one region where a coatinglayer 930, 935 is held in place by an elongated pin formation 925, 927,928, 929, in accordance with some exemplary embodiments of the presentinvention.

In some exemplary embodiments of the invention, a bone plate implant 900is coated by at least one coating layer 930, 935 which covers at leastportions of bone implant surfaces 905, 907, 950, 960, 970. Coating layer930, 935 has at least one aperture shaped and sized to accommodate a pinformation 925, 927, 928, 929 which acts as a retaining structure,tending to restrain the coating layer to the surface 905, 907, 950, 960,970 of the bone plate implant body. Optionally, two or more coatinglayers may share an aperture and pin. In contrast with the circularcross-section pin structures of FIGS. 7A-7E, FIGS. 8A-8E show elongatedpin structures having various forms, including a straight bar 927, aconvex bar 925, a concave bar 928, and a bar curved in the plane of thecoating surface 929. In some embodiments, pin caps from two or moreshanks merge, creating a “staple” geometry which restrains the coatinglayer. These examples may serve to illustrate some of the variety ofretaining structures contemplated, and which may be produced by someoneskilled in the art working according to descriptions herein.

Reference is now made to FIGS. 9A-9C which schematically illustratesectional views of phases in the extrusive formation of a retainingstructure 1250 for restraining a coating layer 1200 to the body 1210 ofa bone plate implant, in accordance with some exemplary embodiments ofthe present invention. These phases are illustrative, provided for thesake of assisting an understanding of aspects of some embodiments of theinvention, and details may vary. Actual extrusion is accomplished byoperations controlled through parameters determined at the macroscopiclevel.

FIG. 9A shows the material of a surface layer 1200 having an aperture1205 overlying the body 1210 of a bone plate implant. In someembodiments of the invention, surface layer 1200 is a metal foil, forexample of titanium or a titanium alloy.

FIG. 9B shows an intermediate stage in structure formation occurringunder a sufficient inward pressure 1225 and/or temperature, as, forexample, occurs during compression molding. Parameters of compressionmolding, including pressure and temperature, disclosed herein as beingappropriate to inducing layer/matrix integration are also appropriate toextrusion formation. Pressure forces melted and/or plasticized boneplate material 1240 to fill the aperture 1205, according, for example,to lines of flow 1235.

As flow occurs, regions 1220 of surface layer 1200 which adjoin aperture1205 may partially collapse. The degree of collapse may depend, forexample, on the distances over which flow occurs, the stiffness of thefoil, and the shape of the mold (which may have protrusions thatsubmerge the foil while allowing matrix material to flow around them).

FIG. 9C shows a formed retaining structure, 1250, which in theembodiment shown includes flanges 1255 formed by backflow which serve toencase an edge region 1260. In some embodiments, formation of retainingstructure 1250 during compression molding is encouraged by leavingspaces in the mold above a place where a retaining structure is desired.In some embodiments, formation of retaining structure 1250 duringcompression molding is encouraged by defining one or more apertures inthe coating material before compression molding. In some embodiments,formation of retaining structure 1250 during compression molding isencouraged by adding material (for example an annulus) to the moldsurface above a place where a retaining structure is desired, so thatthe coating layer is bent slightly inward under pressure.

Not all aspects of the above model of restraint of a coating layer to abone plate implant body by an extrusion are required for an embodimentto function. Flanges are not to scale. They may, for example, berelatively larger or smaller; and/or thicker or thinner. A flange mayextend, for example, for a length as long as the radius and/or width ofthe aperture, or 2 times the aperture size, 4 times the aperture size,10 times the aperture size, or a longer or shorter distance or anydistance in between. The depth of the material protruding above thecoating layer may be, for example, 10% of the layer thickness, 20% ofthe layer thickness, 100% of layer thickness, 1000% of the layerthickness, a larger or shorter depth, or any depth in between. In someembodiments, they are absent. In some embodiments, restraint isaccomplished, for example, by extrusion interactions with a thin end ofthe coating layer. In some embodiments, there is no collapsed region;as, for example, under conditions where substrate flow is sufficientlyfluid. In some embodiments, flow-like plastic deformation of the coatingmaterial (not shown) occurs. Potentially, this also contributes tocoating restraint.

Multi-Layered Coatings

Reference is now made to FIGS. 10A-10D which schematically illustrateperspective views in whole or sectionally, and/or in detail 110, 120, ofexemplary coated bone plate 100 coated on at least one surface 105 by atleast two coating layers 125, 130, in accordance with some exemplaryembodiments of the present invention.

In some exemplary embodiments of the invention, coated bone plate 100 iscoated on at least one surface 105 by at least two coating layers 125,130.

In some embodiments of the invention, innermost coating layer 130 iscomprised of a different material than an overlying coating layer 125.In some embodiments, the material of an inner coating layer 130comprises a bonding layer between an outer surface 140, 150 of theuncoated bone plate material, and an overlying coating layer 125. Insome embodiments, an inner coating layer 130 is chosen that will flowunder conditions of compression molding to produce retaining structures,such as are described, for example, in FIGS. 7A-7E and 8A-8E. In someembodiments, inner coating layer 130 comprises an elastic material, suchas a silicon polymer. A potential advantage of an elastic inner coatingis to distribute stresses at points of contact between bone and implant.In some embodiments, inner coating layer 130 comprises a one or morecomponents of a self-healing system, for example, as described above.

Optionally, the outer surface 140, 150 material is PEEK. Optionally, theouter surface material 140, 150 comprises PEEK and carbon fiber.Optionally, the material of an inner coating layer 130 is PEEK.Optionally, the material of an outer coating layer 125 is a foil ofmetal, for example titanium or a titanium alloy.

In some embodiments of the invention, materials of different layerswithin the volume of a composite implant are chosen to adjust anotherproperty of the implant. For example, the material may be chosen for itsthermal characteristics, electrical properties such as conductivity andcapacitance, for its relative permeability and/or imperviousness to oneor more wavelengths of electromagnetic radiation, or another materialproperty. High thermal conductivity, for example, may provide anadvantage for reducing potentially damaging heat buildup at drillingsites. A relatively high thermal coefficient of expansion may be takenadvantage of in some embodiments to allow, for example, shrink fitting alayer heated during manufacture over an inner core to achieve a firmerattachment upon cooling. In some embodiments, conductivity and/orcapacitance are used in connection, for example, with sensing and/ortelemetry (sensing and telemetry are also related to hereinbelow).Potential advantages for a predetermined electromagnetic opacity aredescribed, for example, in relation to FIGS. 16A-16B, hereinbelow.

Reference is now made to FIGS. 11A-11C which schematically illustratesectional views of phases in the extrusive formation of a retainingstructure 1350 for restraining a surfacing layer 1300 in the presence ofan underlying layer 1305, in accordance with some exemplary embodimentsof the present invention.

The phases of FIGS. 11A-11C are congruent with the phases of FIGS.9A-9C. These phases are illustrative, provided for the sake of assistingan understanding of aspects of some embodiments of the invention, anddetails vary according to the embodiment.

FIG. 11A adds to the surface layer 1300, aperture 1308 and bone plateimplant body 1300 an underlying layer 1305 which is provided withmaterial properties appropriate to serve as the source of extrusionmaterial.

FIG. 11B shows an intermediate stage in structure formation occurringunder a sufficient inward pressure 1325 and/or temperature, as, forexample, occurs during compression molding. Parameters of compressionmolding, including pressure and temperature, disclosed herein as beingappropriate to inducing layer/matrix integration are also appropriate toextrusion formation. Pressure forces melted and/or plasticized boneplate material 1340 to fill the aperture 1305, according, for example,to lines of flow 1335.

As flow occurs, regions 1320 of surface layer 1300 which adjoin aperture1308 may partially collapse. The degree of collapse may depend, forexample, on the distances over which flow occurs.

FIG. 11C shows a formed retaining structure 1350, which in theembodiment shown includes flanges 1355 formed by backflow which serve toencase an edge region 1360. In some embodiments, formation of retainingstructure 1350 during compression molding is encouraged by leavingspaces in the mold above a place where a retaining structure is desired.

A potential advantage of using underlying layer 1305 as a source of fillmaterial is the ability to select filling characteristics different thanthose of the bulk material of the bone plate implant. Optionally, thematerial of underlying layer 1305 provides an extruded appearance whichmasks the color of the bone implant body.

Optionally, the material of underlying layer 1305 is selected so that itflows at a higher or lower temperature than the bulk material of thebone plate implant. This may provide an advantage, for example, if aheat-sensitive agent, such as a healing agent, is to be provided as partof the bone plate implant construction.

Not all aspects of the above model of restraint of a coating layer to abone plate implant body by an extrusion are required in an embodimentfor function. Exceptions and alternatives are discussed herein inrelation to FIGS. 9A-9C.

Retaining Strip

Reference is now made to FIGS. 12A-12D which schematically illustrateperspective views in whole or sectionally, and/or in detail 1010, 1020,of exemplary coated bone plate 1000 coated on at least one surface 1005,and having at least one region where a coating layer 1030 is held inplace by a retaining strip 1025, 1028, in accordance with some exemplaryembodiments of the present invention.

In some embodiments of the invention, one or more lengths of retainingstrip 1025, 1028 are provided. Optionally, retaining strip 1025, 1028 ismade, for example, from PEEK, PEKK, or another suitable material.Optionally, retaining strip lengths 1025, 1028 are portions of a singlestrip length. Optionally, retaining strip lengths 1025, 1028 form acontiguous circumference. In some embodiments, retaining strip 1025,1028 is formed, for example, with a stepped structure, such that it fitsinto a complementary recess in the body of exemplary bone plate 1000.

In some embodiments, material for forming coating layer 1030 is cut sothat it may protrude into the recessed region of bone plate 1000 when itis placed over bone plate surface 1005. While it is so placed, retainingstrip 1025, 1028 inserts into the recess, such that one or more edgeregions of coating layer 1030 are trapped between the strip, 1025, 1028,and the body of bone implant 1000.

In some embodiments, retaining strip 1025, 1028 is bonded to theunderlying bone implant material, for example along surfaces 1050, 1060.Optionally, the bonding occurs under compression molding conditions.

In some embodiments of the invention, an inserted retaining strip islocated within a circumferentially enclosed aperture of a coating layer.Optionally, it is reduced to the size and shape of a plug. Optionally,such a plug-like insert may not have a complementary recess in the bodyof a bone plate, and be bonded instead to the flat surface of the body.In some embodiments, this is an alternative to the extrusion stepsdescribed in FIGS. 9A-9C for producing, for example, restraining pins828, 825, 827, 829, 929, 925, 927, 930 such as are described inconnection to FIGS. 7A-7E, and/or FIGS. 8A-8E.

The use of inserted material for retaining a coating layer provides apotential advantage by allowing pin, plug, and/or strip material to bechosen which has different properties than the underlying bone plateimplant material. For example, it may be of different appearance, orhave different melting or pressure deformation characteristics than thematerial of the underlying implant. Potentially, this allows theconditions of pressure molding to be different, optionally lessstringent (lower pressure or temperature) than otherwise required.Potentially, this allows the appearance of the underlying bone plateimplant body to be entirely masked by either the coating material or theinsert material. In some embodiments, the insert material may itself bestructured, for example, to contain radio-opaque marker material as partof the retaining pin, plug, or strip.

Combinations of Restraint Types

Reference is now made to FIG. 13A which schematically illustrates aperspective view of exemplary coated bone plate 1100 having coatinglayer regions held in place by one or more retaining structures 1110,1125, in accordance with some exemplary embodiments of the presentinvention. This drawing illustrates some of the variety of retainingstructure contemplated in the current invention.

In some embodiments of the invention, retaining strips 1110 (lengths ofstrip like restraining strip 1025), are non-continuous around the edgesof one or more layers 1130, 1120, restraining these layers tocorresponding bone plate implant surfaces 1105, 1107 only inpredetermined places; for example, on the ends of the bone plate.

In some embodiments of the invention, elongated retaining structure 1125is a protrusion restraining one or more layers 1130, 1120 tocorresponding bone place surfaces 1105, 1107 by one or more of themechanisms described in connection with elongated restraining pin 925.In some embodiments, elongated retaining structure 1125 is notcircumferentially surrounded by the material of any single layer. Insome embodiments, the upper and/or lower contours of elongated retainingpin 1125 are non-straight, as shown. This provides the potentialadvantage of improved retaining by gripping retained edges over a longerinterfacing extent, and/or from multiple directions. Optionally, thecontours of elongated structure 1125 are straight.

In some embodiments of the invention, retaining structure 1125 isproduced by compression molding. The material of one or more coatinglayers 1130, 1120 is pre-cut with an edge conforming to the intendedoutline of elongated retaining structure 1125 at the place where theywill contact. Under compression molding, bone plate material undergoesplastic and/or fluid flow. Constrained by edges including the pre-cutedges of coating layers 1130, 1120 some of this material comes tocomprise retaining structure 1125.

Optionally, bone plate 1100 is coated only on one side. Optionally,retaining structure 1125 has a retaining edge only on one side, forexample, on an upper or a lower side. In some embodiments, the otheredge is unformed, as occurs under compression molding when only onecoating layer is provided.

It should be appreciated by someone skilled in the art that theretaining structures herein described are susceptible to combination ona single embodiment of the invention. Exemplary bone plate 1100, forexample, combines a partially circumferential retaining strip 1110 withan elongated retaining structure 1125.

According to the embodiment of the invention, any suitable number,density, and/or relative arrangement of restraining structures is used.For example, restraining structures may occur with a spacing of 1 mm, 2mm, 5 mm, 10 mm, 20 mm, or 50 mm or any distance in between, ordistances larger or smaller. In some embodiments, restraining structuresmay occur with a spacing defined relative to the overall length or widthof the implant, over part or all of one or more implant surfaces; forexample every 1% of the implant length or width, every 2%, every 5%,every 10%, or any distance in between, or distances larger or smaller.Restraining structures are spaced regularly or irregularly. Optionally,restraining structures are concentrated in one or more regions.Optionally, restraining structures are spread across a whole surface.

Reference is now made to FIG. 13B which schematically illustrates aperspective view of exemplary coated bone plate 1150 having coatinglayer regions held in place by one or more retaining structures 1160,1165, in accordance with some exemplary embodiments of the presentinvention. This drawing illustrates some of the variety of retainingstructure contemplated in the current invention.

In some embodiments of the invention, retaining strips 1160, 1165, arenon-continuous around the edges of one or more layers 1170, 1180,restraining them to underlying bone plate implant surfaces only inpredetermined places. In some embodiments, restrained layers cometogether at an angle, and the orientations of the surfaces of attachmentfor retaining strips 1160, 1165 are different from one another. Forexample, retaining strip 1160 may attach to a horizontal (top- orbottom-surface) plane, as shown for retaining strip 1025, whileretaining strip 1165 attaches to a vertical (side surface) plane, inorder to secure the edge of vertically approaching layer 1180. In someembodiments of the invention, portions of a partially coated surface areleft uncoated. This may provide an advantage, for example, in order tobe drilled into without disturbing the coating fixation at other points.In some embodiments, regions left uncoated have different materialproperties than coated regions; for example, material in a regionintended for potential drilling is selected for fracture toughness inpreference to providing stress strength.

In some embodiments of the invention, regions of attachment betweenretaining strips and the underlying material of the bone plate aredetermined in part by the shape and extent of retained layer edges. Forexample, edges of layers 1170, 1180 are cut to be non-straight. In someembodiments, cuts and protrusions of the trapped edges of layers 1170,1180 are interdigitated. This allows one retaining strip 1160 to beexposed to both vertically and horizontally-oriented bone plate surfacesunderneath. In some embodiments, regions of exposure convert underpressure molding conditions into regions of attachment, securing morethan one approaching edge under one retaining strip.

Apertured Layers

Reference is now made to FIGS. 14A-14D which schematically illustrateperspective views in whole or sectionally, and/or in detail 1410, 1420,of exemplary coated bone plate 1400 having an aperture-patterned layer1430 on at least one surface 1407, in accordance with some exemplaryembodiments of the present invention. In some embodiments,aperture-patterned layer 1430 is made of metal, for example titanium. Insome embodiments, aperture-patterned layer 1430 is made of a materialwhich is radio-opaque relative, for example, to the bulk material of thebone plate implant body.

A potential advantage of a coating which comprises a radio-opaque grid,mesh, screen, grating and/or other apertured structure 1460 is tooutline and/or locate all or part of the bone implant in radiographicimages. Outlining and/or position indication in a radiographic image isprovided by the portions of the apertured structure 1460 which areradio-opaque. Another potential advantage of an apertured structure ispartial radiographic transparency due to the incomplete coverage of thebone implant. This potentially permits radiographic visualization ofbone and/or other structures behind the outlined and/or positionindicated bone implant which might otherwise be obscured.

A potential advantage of an apertured coating is to provide additionalflexibility to the coating. In some embodiments, apertures are providedto the coating layer according to the position of screw holes. This mayprovide an advantage for manufacturing; for example, by allowing thecoating to conform to irregular features of the bone implant withouttearing and/or bunching. According to the embodiment, apertures, slits,and other adjustments to the pattern of the coating layer are createdbefore attachment to the bone implant body. A mesh of apertures may beprepared from an extended-surface material substrate; for example bystamping, perforating, slitting, cross-overlaying two or more sublayers,or by another method known in the art. A mesh of apertures may beprepared from strip or wire material; for example by weaving, knitting,winding at crossed angles or by another method known in the art.

In some embodiments, the prepared layer is matched to the bone implantbody during attachment steps so that features such as apertures alignwith appropriate underlying structures.

In some exemplary embodiments of the invention, a bone plate implant1400 is coated by apertured layer 1430, which at least partially coverssurfaces of the bone implant; for example surface 1440 and/or surface1450.

Reference is now made to FIGS. 15A-15D which schematically illustratesurface views of exemplary aperture patterns usable in some embodimentsto comprise apertured layer 1430, in accordance with some exemplaryembodiments of the present invention.

In some embodiments, the apertures of layer 1430 comprise, for example,10% of its area extent, 20% of its area, 50% of its area, 90% of itsarea, or another greater or smaller percentage of its area. In someembodiments, apertures are uniform. For example, FIG. 15A shows apattern of uniform hexagonal apertures. In some embodiments, the shapeof the apertures of layer 1430 is, for example, triangular, circular,square, rectangular, or another shape. In some embodiments, more thanone aperture shape is used. For example, FIG. 15C shows a pattern ofapertures laid out on a rhombus grid, with aperture shapes alternatingbetween circular and rhombus. In some embodiments, apertures arenon-uniform in size and/or shape over the coated surface. For example,FIG. 15D shows a pattern like that of FIG. 15C, with the shapesdistorted. According to the embodiment, distortion occurs duringmanufacturing, for example, to follow a curve of the bone implantdevice. In another example, FIG. 15B shows an irregular hexagonalpattern which is optionally formed as an initial pattern of apertures inlayer 1430. A potential advantage of an irregular pattern is to allowtuning of the relative radio-opacity of different regions of the boneimplant. Another potential advantage of an irregular pattern is tomitigate the formation of resonances due to a repeating structure whichmay produce imaging artifacts. Another potential advantage of anirregular pattern is to allow introducing differential susceptibility todistortion; for example, by using larger and/or more frequent holes inregions where the coating layer must bend through sharper angles toconform to the underlying surface. In some embodiments, the relativespacing of the apertures of layer 1430 is, for example, 0.1 mm, 0.5 mm,1 mm, 5 mm, 10 mm, or another greater or smaller spacing. Optionally,the spacing of the apertures is uniform.

Alternatively, the spacing of the apertures is non-uniform over thecoated surface.

According to the embodiment, the thickness of the apertured meshstructure (coating or embedded in the implant body) ranges, for example:between 100 nanometers and 1 micron, between 1 micron and 10 microns,between 10 microns and 100 microns, between 100 microns and 1 mm, andbetween 1 mm and 2 mm. In some embodiments, a different thickness isused at different regions of the implant.

According to the embodiment, layer 1430 is constructed, for example: ofa perforated foil; of woven, knotted or braided wires; of overlaid wiresor foil strips; of wound wire or foil stripping, or by anotherconstruction suitable for forming a structure of alternating aperturesand radio-opaque material. In some embodiments, layer 1430 is comprisedof a potentially unperforated polymer sheet to which an aperturedpattern of a radio-opaque material has been attached, for example byspraying, painting, and/or dipping. In some embodiments, layer 1430 isapplied together with one or more other layers. The pattern of apertures(or gaps) and aperture- or gap-defining material formed by layer 1430may be striped; for example, as could be constructed by spirally windingone or more wires or foil strips, optionally of radio-opaque material,around a bone implant. According to the embodiment, the orientation ofthe pattern of apertures may be in any direction.

Reference is now made to FIGS. 16A-16B which schematically illustrate inperspective sectional view regions of exemplary bone implants (whichare, for example, sized and shaped overall like exemplary coated boneplate 1400; or, alternatively, have the shape of another bone implantherein described, or of another bone implant shape known in the art)having an apertured layer 1620, 1630 embedded within the implantstructure, in accordance with some exemplary embodiments of the presentinvention. In some embodiments, layer 1620 is overlaid on the body 1622of a bone implant, and itself overlaid by an additional coating layer1618. In some embodiments, layer 1630 is embedded within the material ofthe body 1622 of a bone implant; for example, during a stage ofmanufacturing in which the body is being originally formed. In someembodiments, an apertured layer 1620, 1630 is radio-opaque.

In some embodiments, the pattern of radio-opaque material formed bylayer 1430 is chosen to minimize artifacts in magnetic resonance imaging(MRI) images. For example, the aperture size and/or spacing is chosen toreduce an amount of metal present in layer 1430. Optionally, theaperture size and/or spacing are adjusted to change the placement ofmaterial formed by layer 1430 so that artifacts affecting tissuevisualization in MRI images are reduced. In some embodiments, theformation of eddy currents affecting MRI images is reduced by theapertures which break and thereby shorten the available pathways forcurrent circulation.

In some embodiments, radio-opaque elements are provided as separateelements. Elements may be arranged in an encoding pattern foridentification, and/or arranged to delineate the position of one or morefeatures of the bone implant.

Encoding may be, for example, by providing a specific pattern of groupedelements, a specific number of grouped elements, and/or providinggrouped elements with different relative transparencies. In someembodiments of the invention, radio-opaque elements are positioned on acoating layer before attachment of the coating with a predeterminedlocation and/or orientation.

Materials which may be used in a radio-opaque marker include, forexample, titanium, tungsten, barium sulfate, and zirconium oxide.

Identification and/or Telemetry

In some embodiments of the invention, one or more coating layers areprovided with electronic circuitry. In some embodiments, the circuitryincludes one or more radio frequency identification (RFID) tags whichare interrogated to report an identifying code or other information. Insome embodiments, patterning of the coating layer itself comprises aportion of the electronic circuitry, for example, an antenna for an RFIDdevice. In some embodiments, an RFID device is embedded in the body ofthe bone implant. In some embodiments, the circuit provides biotelemetrythrough implementing a wireless identification and sensing platform(WISP) or other telemetry platform. In some embodiments, one or morebiotelemetry circuits are provided with a sensor; for example, with astrain sensor. Optionally, the strain sensor senses multiple strainvalues through a range. Optionally, the strain sensor is a fuse-typesensor, which detects, for example by breaking, whether a preset strainlevel has been exceeded during the lifetime of the device. A potentialadvantage of strain sensing is to alert to the possibility of damageleading to device failure in a bone implant device.

Detail Coating

Reference is now made to FIGS. 17A-17B, which schematically illustratemold and part components for coating of a bone screw by compressionmolding, in accordance with some exemplary embodiments of the presentinvention.

In some embodiments of the invention, manufacturing of a compositematerial implant comprises attachment by compression molding of a thinmetal film to an implant surface comprising fine details. In someembodiments, the surface details to be coated comprise a screw thread,for example, the thread of a bone screw. In some embodiments, the coatedsurface details comprise another surface feature, such as identifyingmarks, raised or indented texturing, and/or fine cut-outs orprotrusions.

In some embodiments, mold components 1710, 1720 comprise reverse-reliefimpressions accommodating the contours of the component 1730 to becoated.

Optionally, the impressions accommodate the contours with a gapsufficient for accommodating the coating layer as well, and/or the gapis optionally larger than needed for accommodating the coating layer. Insome embodiments, component 1730 comprises a composite construction,such as carbon fiber-PEEK, or another composite construction, forexample as described hereinabove.

In some embodiments, details of component 1730 to be coated comprisestructures having a smallest dimension of, for example, 100-250 μm200-500 μm, 400-800 μm, 500-1000 μm, or another larger or smaller rangeof smallest dimensions. A smallest dimension may be, for example, thedistance across a thread protrusion, thread incision, and/or thethickness of a line in an embossed character. In some embodiments, asharp radius of curvature is accommodated, for example, a radius down toa size of 50-100 μm, 75-150 μm, 100-250 μm, 200-500 μm, 400-800 μm,500-1000 μm, or another larger or smaller curvature radius.

In some embodiments of the invention, the mold tolerances arepredetermined so that the mold itself directly presses the coating layerto the part to be coated. In some embodiments, the mold tolerance islarger. Optionally, a pressing fit is obtained, for example, by use ofan outer material for filling gaps in the mold. The filler material is,for example, PEEK, or another plastic resin suitable for compressionmolding together with the component, for example as described inconnection with compression molding hereinabove. Optionally, the outerfiller material is removed after compression molding, leaving behind thecoated component 1730.

In some embodiments, the coating material is a thin metal foil 1740,comprising, for example, titanium, titanium alloy and/or stainlesssteel. In some embodiments, the coating material is a polymer 1740,comprising, for example, PEEK and/or PEKK.

The thickness of the metal film is, for example, 2-20 μm 10-40 μm, 25-50μm, 40-80 μm, 50-100 μm, 75-150 μm, 140-200 μm, a wider or narrowerrange of thicknesses, or range comprising thicker or thinner filmthicknesses.

In some embodiments, another coating material is used, for example atape or other coating material as described in connection with othercoated embodiments hereinabove. In some embodiments, the coatingmaterial is placed within the mold 1710, 1720 between the mold surfaceand the material of the component to be coated.

In some embodiments, the coating material is placed as a winding, asheet, a tube, or in another for suitable for bringing the coatingmaterial into close association with the component to be coated. In someembodiments, the coating material is previously shaped with a screwthread or other shape, for example to accommodate the thread of a bonescrew. Optionally, another preparation of the coating material forms itinto a shell for fitting more closely to the component to be coatedbefore a compression molding process.

In some embodiments, the coating material undergoes a compressionmolding process together with the coated component.

In some exemplary embodiments of the invention, the molding processresults in the adhesion of a metal foil to the material of the coatedcomponent. Potentially, this confers an increase resistance to shearforces (forces parallel to the metal film). In some embodiments, theadvantage conferred is another of the advantages described in connectionwith different coatings described hereinabove.

In some embodiments, adhesion is less resistant to forces perpendicularto the metal foil or other coating material. Optionally, the metal shellis peelable from the component after removal from the mold. A potentialadvantage for a peelable shell is to reduce adherence of a compositematerial to the mold as a result of compression molding. Anotherpotential use of a peelable shell is to use the preformed shell shape toimpress onto the component shapes (for example, an inner thread for ahole) which are difficult to non-destructively release from a moldblock.

Bone Nail Coating

FIG. 18 schematically illustrates a bone nail coated with PEEK bycompression molding, in accordance with some exemplary embodiments ofthe present invention.

In some embodiments, a coated bone implant comprises acomposite-construction bone nail (intramedullary nail) 1800. In someembodiments, the body of the composite-construction bone nail iscomprised of carbon fiber-PEEK composite.

In some embodiments, a composite-construction bone nail is coated withPEEK using compression molding, for example as described hereinabove forbone implants of other shapes and/or types. In some embodiments, a bonenail 1800 is wrapped in a PEEK tape, and undergoes a compression moldingstep. In some embodiments, an added layer of PEEK does not comprisecarbon fibers and/or another fiber reinforcement material present in theunderlying composite construction.

Potential advantages of this include modification of a surfaceappearance, modification of the amount and/or appearance of particleshedding, and/or other potential advantages as described hereinabove inrelation to bone implant coatings for bone implants such as bone platesand bone screws. In some embodiments of the invention, anothercomposite-construction bone implant component is coated with asuperficial layer of PEEK, for example, a bone plate and/or a bonescrew.

In some embodiments, bone nail 1800 comprises radiopaque markers 1803.In some embodiments, radiopaque markers 1803 are added to bone nail 1800during the compression molding operation, for example by adding themarkers underneath a wrapping PEEK tape or by otherwise incorporatingthem along with the wrapping material.

In some embodiments of the invention, bone nail 1800 comprises holes1801, 1801A, 1802. In some embodiments, holes are threaded (seen incross-section at holes 1801A, 1802). Holes 1801, 1801A, in someembodiments, comprise holes for receiving bone screws. Optionally,radiopaque markers 1803 are located near holes 1801, 1801A to assist inhole localization during implantation. In some embodiments of theinvention, hole 1802 comprises a receiving hole for an implantationhandle, which is optionally attached during implantation to assist inthe implantation procedure. In some embodiments, one or more of holes1801, 1801A, 1802 are coated and/or lined in a compression moldingprocess, for example as described for bone plate holes hereinabove.

As used herein the term “about” refers to 10%.

The terms “comprises”, “comprising”, “includes”, “including”, “having”and their conjugates mean “including but not limited to”.

The term “consisting of” means “including and limited to”.

The term “consisting essentially of” means that the composition, methodor structure may include additional ingredients, steps and/or parts, butonly if the additional ingredients, steps and/or parts do not materiallyalter the basic and novel characteristics of the claimed composition,method or structure.

As used herein, the singular form “a”, “an” and “the” include pluralreferences unless the context clearly dictates otherwise. For example,the term “a compound” or “at least one compound” may include a pluralityof compounds, including mixtures thereof.

Throughout this application, various embodiments of this invention maybe presented in a range format. It should be understood that thedescription in range format is merely for convenience and brevity andshould not be construed as an inflexible limitation on the scope of theinvention. Accordingly, the description of a range should be consideredto have specifically disclosed all the possible subranges as well asindividual numerical values within that range. For example, descriptionof a range such as from 1 to 6 should be considered to have specificallydisclosed subranges such as from 1 to 3, from 1 to 4, from 1 to 5, from2 to 4, from 2 to 6, from 3 to 6 etc., as well as individual numberswithin that range, for example, 1, 2, 3, 4, 5, and 6. This appliesregardless of the breadth of the range.

Whenever a numerical range is indicated herein, it is meant to includeany cited numeral (fractional or integral) within the indicated range.The phrases “ranging/ranges between” a first indicate number and asecond indicate number and “ranging/ranges from” a first indicate number“to” a second indicate number are used herein interchangeably and aremeant to include the first and second indicated numbers and all thefractional and integral numerals therebetween.

It is appreciated that certain features of the invention, which are, forclarity, described in the context of separate embodiments, may also beprovided in combination in a single embodiment. Conversely, variousfeatures of the invention, which are, for brevity, described in thecontext of a single embodiment, may also be provided separately or inany suitable subcombination or as suitable in any other describedembodiment of the invention. Certain features described in the contextof various embodiments are not to be considered essential features ofthose embodiments, unless the embodiment is inoperative without thoseelements.

REFERENCES

-   S Beauvais, O Decaux; Plasma Sprayed Biocompatible Coatings on PEEK    Implants.-   S W Ha et al.; Topographical characterization and microstructural    interface analysis of vacuum-plasma-sprayed titanium and    hydroxyapatite coatings on carbon fibre-reinforced    poly(etheretherketone), Journal of Materials Science: Materials In    Medicine (1997) 8:891-896.-   M A Rahamathunnisa et al.; Coatings on Composites, Lappeenranta    University of Technology, Faculty of Technology, Department of    Mechanical Engineering, Research Report No. 74, ISBN    978-952-214-504-8, ISSN 1459-2932, Mikkeli (2007).-   E Lugscheider et al.; Magnetron sputtered titanium nitride thin    films on thermoplastic polymers, Surface and Coatings    Technology (1999) 116-119.-   H S Kim, H J Jung Kim; Detorque force of TiN-coated abutment screw    with various coating thickness after repeated closing and opening, J    Korean Acad Prosthodont (2007) 45:1172-1178.-   G Williams et al.; A self-healing carbon fiber reinforced polymer    for aerospace applications, Composites: Part A (2007) 38: 1525-1532.-   E T J Rochford et al.; In vitro investigation into bacterial    adhesion to medical grade PEEK surfaces, 56th Annual Meeting of the    Orthopedic Research Society (2010) Poster 666.-   A Simchi et al.; recent progress in inorganic and composite coatings    with bacterial capability for orthopedic applications, Nanomedicine:    nanotechnology, biology and medicine (2011) 7:22-39,-   Xing Zheng et al.; lubrication of polyether ether ketone (PEEK)    surface by liquid ultrathin films for high wear durability,    Wear (2012) 296:681-692.-   K Hargou et al.; Ultrasonic activation of mendable polymer for    self-healing carbon-epoxy laminates, Composite, Part B, in press    (2012).-   E L Steinberg et al.; Carbon fiber reinforced PEEK Optima—A    composite material biomechanical properties and wear/debris    characteristics of CF-PEEK composites for orthopedic trauma    implants, J Mech Behav Biomed Mater, (2013) 17:221-8.-   ATI Ti-6Al-4V, Grade 5 technical data sheet VERSION 1 (Jan. 31,    2012).

What is claimed is:
 1. An implantable bone plate comprising: a body offiber-reinforced polymer composite construction; and at least one layerconfigured to cover an exterior facing surface region of said body wherethe layer contacts bone when implanted; wherein the layer is made ofmetal such that the body is shielded from wearing contacts with bonewhen implanted; and wherein at least one edge region of said at leastone layer is encased by material of said bone plate.
 2. An implantablebone plate according to claim 1 wherein said material comprises aportion of said body.
 3. An implantable bone plate according to claim 2wherein said material comprises an extrusion of said body.
 4. Animplantable bone plate according to claim 3 wherein said extrusioncomprises a shank and a head; the shank being attached at one end to thebody, and the head being attached to the other end of the shank; thehead being sized and positioned to interfere with the movement of saidat least one layer relative to the body.
 5. An implantable bone plateaccording to claim 3, wherein said extrusion is flanged.
 6. Animplantable bone plate according to claim 1, wherein said materialcomprises at least a portion of an at least second layer.
 7. Animplantable bone plate according to claim 6 wherein said at least secondlayer overlaps and conforms against at least a portion of said edgeregion.
 8. An implantable bone plate according to claim 1, wherein saidmaterial comprises a restraining strip.
 9. An implantable bone plateaccording claim 8 wherein said restraining strip is bonded to said body.10. An implantable bone plate according to claim 8, wherein said edgeregion of said layer is held within a recess of said body, said recessbeing at least partially filled by said restraining strip.
 11. Animplantable bone plate according to claim 8, wherein said edge region ofsaid layer comprises a portion which is bent and within a recess of saidbody, said recess being at least partially filled by said restrainingstrip.
 12. An implantable bone plate comprising: a body offiber-reinforced polymer composite construction; and at least one layerconfigured to cover an exterior facing surface region of said body wherethe layer contacts bone when implanted; wherein the layer is made ofmetal such that the body is shielded from wearing contacts with bonewhen implanted; wherein at least a portion of said body is conformedagainst an edge surface of said at least one layer; and wherein saidconformed portion comprises a pin.
 13. An implantable bone plateaccording to claim 1, wherein at least a portion of said layer is madeof titanium.
 14. A method for manufacturing an implantable bone platecomprising: forming a body of fiber-reinforced polymer compositeconstruction, preparing at least one metal coating layer for the boneplate, and compression molding the bone plate together with the preparedat least one metal layer; such that the at least one metal coating layeris restrained against the surface of said body; wherein at least oneedge region of the at least one metal coating layer is encased bymaterial of said bone plate; and wherein said preparing comprisespositioning said metal coating layer with respect to a surface of thebody shaped and positioned with respect to the body for positioningagainst bone so that it shields said surface from wearing contacts withbone when implanted.
 15. The method of claim 14, wherein said preparingcomprises perforating said at least one coating layer.
 16. Animplantable bone plate according to claim 12, wherein at least a portionof said layer is made of titanium.
 17. A method for manufacturing animplantable bone plate comprising: forming a body of fiber-reinforcedpolymer composite construction, preparing at least one metal coatinglayer for the bone plate, and compression molding the bone platetogether with the prepared at least one metal layer; such that the atleast one metal coating layer is restrained against the surface of saidbody; wherein at least a portion of said body is conformed against anedge surface of said at least one layer; and wherein said conformedportion comprises a pin; and wherein said preparing comprisespositioning said metal coating layer with respect to a surface of thebody shaped and positioned with respect to the body for positioningagainst bone so that it shields said surface from wearing contacts withbone when implanted.
 18. The method of claim 17, wherein said preparingcomprises perforating said at least one coating layer.